Automatic fluid flow shutoff device

Abstract

An emergency gas flow shutoff device for use primarily with gas cylinder operations. When there is a sudden loss of resistance downstream of the device due to a cut hose or a fire from a severed hose a ball located in the device completely closes off an orifice to stop further gas flow. The device also incorporates a gas flowmeter or pressure gauge as part of the reset mechanism thus eliminating additional connectors.

I claim: 
     
       1. A fluid flow shutoff device comprising: a body, a chamber within said body, an inlet and an outlet communicating with said chamber to permit fluid flow through said chamber, said outlet defining an outlet orifice connected to an outlet passage, a ball valve located and captured in said chamber to one side of said orifice and permitting fluid flow through said orifice to said outlet passage under a steady flow regime or gradually increasing flow regime of fluid through said chamber but seating upon and closing said orifice to arrest said fluid flow under a sharply increasing flow regime of said fluid through said chamber, a hollow shaft slidably mounted within said body at the other side of said orifice and coaxial therewith and being connected to a pressure measuring gauge for measuring via said hollow tube fluid pressure in said outlet passage, and resilient means urging said hollow shaft away from said orifice whereby depression of said hollow shaft against said resiliently means effect unseating of said ball valve from said orifice wherever restarting of fluid flow is required.   
     
     
       2. A fluid flow shutoff device as claimed in claim 1, comprising also an actuator rod slidable with clearance along a bore which extends through said chamber and between said inlet and said outlet to effect control of the supply of fluid via a needle valve in a gas cylinder connected at said inlet, a recess in said rod, a detent in said chamber engageable within said recess to limit the sliding movement of said rod, and a fluid seal between said rod and said bore preventing fluid leak along said bore to said outlet.